Modern printing system as commonly used for processing printed circuit boards, solar cells, films or the like work according to the principle that substrates are successively fed to a printing device via a feeding system and are aligned in the printing device with respect to a printing template, are printed and subsequently conveyed away. For the alignment it is known to provide cameras and image evaluation systems which optically detect the substrate in order to then be able, with the knowledge of the arrangement of the camera(s) with respect to the printing template, to optimally align the substrate with respect to the printing template. For this purpose it is known, for example, to move and/or rotate a printing table on which the substrate is placed for printing until the substrate is positioned congruent to the printing template. Only then a printing process is performed, for example by means of a scraper of the printing device, in which the printing medium is applied onto the substrate through the printing template, which can be a printing screen or a printing mask, for example.
Optically detecting the alignment of the substrate or the substrates offers very high accuracy and allows the processing of many different types and shapes of optical orientation tags and/or identification tags that are applied on the substrates. Once the printing process is completed, the substrate is removed again from the printing device and it is optionally inspected in advance or afterwards as to whether the printing process has been performed successfully. However, optically detecting the substrate or substrates has the disadvantage that optical orientation tags have to be applied on each of the substrates and optionally also on the printing template. Also, providing orientation tags on the substrates results in the act that no other elements such as circuit elements or the like can be provided in the region of the orientation tag(s), which can limit the utilization of the surface of the substrate during printing.